(1) The amorphous, gel-like, noncellular component of the extracellular matrix where the fibers and cells of connective tissue are embedded.
(2) The clear, fluid portion of the cytoplasm of the cell; hyaloplasm.
In connective tissues, the ground substance is primarily composed of proteoglycans, glycosaminoglycans, glycoproteins, water, and ions. It fills the space between cells of connective tissue.
Also called: substantia fundamentalis.